In modern telecommunication networks such as convergence networks, a plurality of entities may be deployed for providing communication services. However, if e.g. a network entity under management is not performing at a service level as expected by a network operator, then a single network incident may result in generation of multiple alarms from affected entities under management and management systems, over space and time. The network operator receiving the generated alarms may be enabled to evaluate the received alarms to determine the impact for the end subscribers on a communication service such as voice, and identify the entity having the network fault. In this regard, rapid and accurate determination of end user impact and faulty entity may shorten the time to repair, reduce operational costs, and facilitate the support of service contracts between operators providing communication services and service consumers.
By studying the WLA (Work Level Agreement) and SLA (Service Level Agreement) between the operator and Managed Service Provider, it may be found out that the judgment on severity of an incident in the network has fundamental differences to the perceived severity an alarm provided by the network element or network entity (NE). The severity of an incident, seen from the operator point of view, is judged by the impact on the delivered services and revenue. Examples of KPI (Key Performance Indicators) used by operator for severity judgment are:                Number of affected subscribers,        Number of affected sites,        The level of disturbance,        The affected communication service,        Type of site affected (golden site, A-site, B-site),        Affecting or non affecting important customers, or        Certain important events in an area like music festival, football etc.        
For the perceived severity on an alarm, in ITU-T X.733 chapter 8.1.2.3, which 3GPP fault management standard TS 32.111-1 is referred to, the perceived severity is divided into 6 different categories: cleared, indeterminate, critical, major, minor and warning. Only two of the categories, critical and major, indicate a service affecting condition has developed. Unfortunately, there is no information on the quantity of the service is affected on the network.
The current 3GPP standard TS 32.121 states that the IRP Manager (Network Management System) should be able to request the IRP Agent (Domain Manager) to categorize the alarm with rules. These rules may depend for example on the type of alarm, the environment, the time of day, the type of network element, the alarm severity, the location, position in the containment tree etc. However, this approach of categorization of alarm requires detailed knowledge of the network element, how the elements are structured in between (position in the containment tree) and also knowledge of the alarms (type of alarm, alarm severity).
Due to lack of quantification of the affected service, it is difficult to make an automatic judgment of severity based on the network impact as described in the WLA/S LA.